Electronic animal control systems have been used wherein a radiofrequency receiver device is mounted upon an animal to control the movement of the animal relative to a predetermined area such as a yard. A transmitter that produces a predetermined electromagnetic signal is connected with a transmission antenna positioned at the selected area for radiating the electromagnetic signal at the selected area such as along the perimeter of the area. The receiver device is adapted to detect the predetermined electromagnetic signal and, in response; deliver a correction stimulus, such as a mild shock or audible signal, to the animal. It has been observed in the operation of various animal control systems, that the selected area relative to which the movement of the animal is to be controlled, often includes incidental conductive structures that can couple and re-radiate the transmitter signal in undesired areas. The incidental structures function as "coupling structures" relative to the transmitter signal radiated from the transmission antenna. For example, residential locations are often supplied with various utilities, such as water, cable television, electrical power, telephone service, and the like, by overhead or underground conductors (pipes, wires, cables, &c.) that cross the property lines of the residence and then are distributed throughout the residence. Depending upon the topology of the conductors or their proximity to the transmitting antenna along their respective routes, the transmitter signal can induce a similar signal within such conductors. The conductors may then, in effect, distribute the transmitter signal to undesired locations at the residence by re-radiating the induced signal along their respective routes.
Other conductive or metallic structures within or about the vicinity of the transmission antenna at the selected area may also act as undesirable coupling structures. For example, a metallic door frame can provide a conductive loop that acts as a receiving antenna for coupling the signal generated by the transmitter. Although the transmitted signal may be relatively weak in the vicinity of the door frame, the door frame may happen to have an electrical characteristic that sufficiently resonates at the carrier frequency to amplify the coupled signal and to radiate the amplified signal.
The primary undesirable result of the presence of incidental coupling structures is that the animal occasionally receives the correction stimulus in areas where the stimulus is not intended to be applied. Such unintended stimulation of a dog can habituate the dog to being stimulated by the receiver, thus contributing to decreased effectiveness of the animal control system to confine the dog. Additionally, such unintended stimulation can contribute to undesirable behavior of the dog.